Evinrude 4hp twin

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imported_Ranger

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Hi, can anyone help me? I have just been given an Evinrude 4hp outboard that has been lying in a garage for many years. After a few days tinkering about with it, replacing fuel hoses and cleaning the carb it burst into life. This is the first outboard i have owned and know nothing about them. Can anyone please tell me what year it is, the numbers on the engine are 43B36C and B49006. I ran the engine for 30secs as a dont know how to check the water pump. I would like to fit a new water pump before i take it out. Is it an easy job to do? I used to be a car mechanic but not sure where the impeller is located hence the reason to find out the year and try to locate a repair manual. Any help would great. Thanks.
 
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Paul Moir

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Re: Evinrude 4hp twin


Welcome to Iboats, Ranger!

The 43B36C was built in 1973, and is a Belgian plant variant of the 4hp engines. It's a little different from the North American 4hp engines so I don't have a whole lot of information on it. I believe it was called the MiniTwin. There's some information on it here if you want to practice your Italian:
http://digilander.libero.it/OLDMERCS/storia/lightwin.htm

I think the water pump is a very simple task on that outboard though. Just unbolt the lower unit (4 bolts) and drop it to access the water pump. When you take the pump cover off be careful not to pull up on the driveshaft as the only thing holding it in is the impeller at that point. At least I think that's the case on the MiniTwin!

To determine if the water pump is operating, you should feel a mist along with the idle exhaust which comes out the little holes in the leg. Also, dribble a little water on the head (if it's not impossible on that model) - the water should steam away but not sizzle. There's a possible fault with the 4hp where the water pump will seem to operate properly but the engine still overheats.
 
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imported_Ranger

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Re: Evinrude 4hp twin

Had a look at the link you sent and the motor I have looks slightly different having a fuel tank on top.But its the closest yet. Thanks again!
 
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imported_Ranger

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Re: Evinrude 4hp twin

Thanks again Paul.
Came home from work tonight and decided to have another go at it. Can't find the four bolts required to remove the lower leg (unless its four rusty flathead screws at the top) To be honest I took off the prop because someone told me it would be behind that. Then removed the two bolts behind that and covered myself in mucky gear oil. I think its time to call on profesional help as its very clear that car engines are totally different to outboards. Sorry to be a pain and thanks for taking the time to help.
 
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Paul Moir

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Re: Evinrude 4hp twin

Oh, that's where it would have been if the engine was built in the fourties. But things have changed since then.

Sorry, I'm not 100% familiar with that engine. The powerhead looks like a regular 4hp one but that's where the similarities end.

I think this diagram matches yours:
convert

The 2 bolts that hold it on are 11 and 17. The impeller is 16.

I agree about the auto engines, the pistons don't even look the same! :D
 
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imported_Ranger

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Re: Evinrude 4hp twin

The diagram is fantastic. This is what I have been looking for. Due to work I won't be able to try this until the weekend, so I'll let you know how I get on. Thanks again for helping a real novice.
 
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imported_Ranger

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Re: Evinrude 4hp twin

Hi Paul

Got the impeller out and have a new one on the way.
The fins on the impeller were well worn.
The diagram was spot on. Thanks again for your help.
 
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Paul Moir

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Re: Evinrude 4hp twin

Thanks for the reply.

The trouble with impellers is, the rubber gets old over time and sometimes when you put them back in service they fly apart. Then the bits end up clogging up the cooling system.

When you go to put it back together, a little dish soap will aid in assembly. Also, use gasket sealer on all the screw and bolt thread to prevent them from corroding together. You can also substitute grease but I like sealer better.
Avoid anti-sieze, especially the copper stuff. It'll wreak havoc if the engine is run in salt water.

Also, lightly grease the splines on the top of the driveshaft to prevent corrosion and wear. While you're at it, take the propeller off and spread some grease on the propshaft. (Can you tell we have salt water here?)

It looks like your 4hp is a cross between the early '70s 2 horsepower and 4 horsepower engines. It has the lower unit, pull starter, and I think midsection from the 2hp, but with a 4hp engine bolted on to it.
 
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imported_Ranger

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Re: Evinrude 4hp twin

Hi Paul,

Got the new impeller fitted today and everything else cleaned and greased. I ran the engine for about 10mins. there was mist coming from the little holes in the leg as you stated earlier and the leg was much cooler than the first time I started it. The cylinder head did get very hot to touch but as I sprayed water onto it there was no sizzling. Fingers crossed that it will be ok. I was expecting to see water pouring out the holes but it was only dribbling out. Before putting the leg back together I attatched a hose to the water pipe to blast through the engine and it seemed to run out the leg ok.
Once again, many thanks for all your help.
Stuart.
 
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